Practical
Plants

Alnus glutinosa

Alder

a perennial woody deciduous member of the Alnus genus in the family Betulaceae.

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Taxonomy and growth

Genus
Alnus
Life cycle
perennial
Foliage
deciduous
Woodiness
woody
Growth rate
vigorous
Height
25 m
Spread
10 m
Fertility
Wind
Flower type
monoecious
Pollinators
Wind

Uses

Medicinal uses

Historical medicinal uses. These records describe reported uses. They do not establish safety or effectiveness. Ask a qualified health professional before using any plant medicinally.

This section contains historical Plants For A Future notes marked noncommercial.

The bark is alterative, astringent, cathartic, febrifuge and tonic[18][24][6][19][16]. The fresh bark will cause vomiting, so use dried bark for all but emetic purposes[10]. A decoction of the dried bark is used to bathe swellings and inflammations, especially of the mouth and throat[18][27][10][14]. The powdered bark and the leaves have been used as an internal astringent and tonic, whilst the bark has also been used as an internal and external haemostatic against haemorrhage[10]. The dried bark of young twigs are used, or the inner bark of branches 2 - 3 years old[27]. It is harvested in the spring and dried for later use[27]. Boiling the inner bark in vinegar produces a useful wash to treat lice and a range of skin problems such as scabies and scabs[10]. The liquid can also be used as a toothwash[10]. The leaves are astringent, galactogogue and vermifuge[24]. They are used to help reduce breast engorgement in nursing mothers[14]. A decoction of the leaves is used in folk remedies for treating cancer of the breast, duodenum, oesophagus, face, pylorus, pancreas, rectum, throat, tongue, and uterus[16]. The leaves are harvested in the summer and used fresh[12].

Product or use
Alterative
Product or use
Astringent
Product or use
Cathartic
Product or use
Emetic
Product or use
Febrifuge
Product or use
Galactogogue
Product or use
Haemostatic
Product or use
Parasiticide
Product or use
Skin
Product or use
Tonic
Product or use
Vermifuge

Material uses

This section contains historical Plants For A Future notes marked noncommercial.

Tolerant of clipping and maritime exposure, the alder can be grown in a windbreak or a hedge[25]. The trees are very quick to establish[9] and will grow at a rate of 1 metre or more per year when young[K]. This is an excellent pioneer species for re-establishing woodlands on disused farmland, difficult sites etc. Its fast rate of growth means that it quickly provides sheltered conditions to allow more permanent woodland trees to become established. In addition, bacteria on the roots fix atmospheric nitrogen - whilst this enables the tree to grow well in quite poor soils it also makes some of this nitrogen available to other plants growing nearby. Alder trees also have a heavy leaf canopy and when the leaves fall in the autumn they help to build up the humus content of the soil. Alder seedlings do not compete well in shady woodland conditions and so this species gradually dies out as the other trees become established[K]. Because they tolerate very poor soils and also produce nitrogen nodules on their roots, alders are suitable for use in land reclamation schemes. The plants can be used as a source of biomass[16]. According to the phytomass files, annual productivity is estimated at 6 to 9 tonnes per hectare. The tree has yielded 11.8 tonnes per hectare per annum on pulverized fuel ash and annual productivity has been estimated at 8.66 tonnes per hectare, with 5.87 tonnes in wood, bark, and branches, 2.79 tonnes in foliage[16]. Alder has been recommended for consideration for firewood plantations in Tropical highlands where unseasonable cold might destroy the red alder[16]. The powdered bark has been used as an ingredient of toothpastes[27]. Sticks of the bark have been chewed as tooth cleaners[27]. An ink and a tawny-red dye are obtained from the bark[18][21][24][23]. A green dye is obtained from the catkins[18][21][23]. A pinkish-fawn dye is obtained from the fresh green wood[18][21][23]. A yellow dye is obtained from the bark and young shoots[18][21][23]. A cinnamon dye is obtained from the shoots if they are harvested in March[18]. If they are dried and powdered then the colour will be a tawny shade[18]. The bark and the fruits contain up to 20% tannin[19][22][11], but they also contain so much dyestuff (imparting a dark red shade) that this limits their usefulness[18][24]. The leaves are also a good source of tannin[18]. The leaves are clammy and, if spread in a room, are said to catch fleas and flies on their glutinous surface[18][24]. Wood - very durable in water, elastic, soft, fairly light, easily worked, easily split. It is often used for situations where it has to remain underwater and is also used for furniture, pencils, bowls, woodcuts, clogs etc. It is much valued by cabinet makers[18][24][3][5][15][19][23][2][4]. The wood also makes a good charcoal[18][4].

Product or use
Charcoal
Product or use
Dye
Product or use
Ink
Product or use
Insecticide
Product or use
Tannin
Product or use
Dental care
Product or use
Wood

Ecology and functions

Ecosystem niche
Canopy

Environment

Range
Most of Europe, including Britain, to Siberia, W. Asia and N. Africa.
Habitat
Wet ground in woods, near lakes and along the sides of streams, often formng pure woods n succession to marsh or fen[27].
Light
full sun
Shade tolerance
light shade
Water
high
Hardiness
Zone 3+
Soil textures
loamy, clay, heavy clay
Soil pH
acid, neutral, alkaline
Tolerances
high wind, maritime exposure
Wind
Yes
Maritime
Yes
Tolerates Nutritionally Poor Soil
No
Drought
intolerant

Propagation

This section contains historical Plants For A Future notes marked noncommercial.

Seed - best sown in a cold frame as soon as it is ripe and only just covered[9]. Spring sown seed should also germinate successfully so long as it is not covered[200, K]. The seed should germinate in the spring as the weather warms up. When large enough to handle, prick the seedlings out into individual pots. If growth is sufficient, it is possible to plant them out into their permanent positions in the summer, otherwise keep them in pots outdoors and plant them out in the spring. There are about 700,000 - 750,000 seeds per kilo, but on average only about 20 - 25,000 plantable seedlings are produced[16]. Seeds can remain viable for at least 12 months after floating in water[16]. Seeds germinate as well under continuous darkness as with normal day lengths. Air-dried seeds stored at 1 - 2°C retained their viability for two years. Seeds can however be sown immediately as soon as ripe[16]. If you have sufficient quantity of seed, it can be sown thinly in an outdoor seed bed in the spring[26]. The seedlings can either be planted out into their permanent positions in the autumn/winter, or they can be allowed to grow on in the seed bed for a further season before planting them. Cuttings of mature wood, taken as soon as the leaves fall in autumn, outdoors in sandy soil.

Cultivation

This section contains historical Plants For A Future notes marked noncommercial.

Prefers a heavy soil and a damp situation[1][3], tolerating prolonged submergence of its roots and periods with standing water to 30cm deep[8][9]. Plants can also grow quickly in much drier sites, though they will usually not live for so long in such a position. Alders grow well in heavy clay soils[13][28], they also tolerate lime and very infertile sites[9]. Tolerates a wide range of soils but prefers a pH above 6[8]. Very tolerant of maritime exposure[20][25][7]. Alder is estimated to tolerate an annual precipitation of 40 to 200cm, an annual average temperature of 8 to 14°C and a pH of 6 to 8[16]. The leaves often remain green on the tree until November, or even later on young seedlings. The seeds contain a margin of air-filled tissue and are capable of floating in water for 30 days before becoming waterlogged[8]. This enables distribution of the seed by water. The alder has a very rapid early growth[28], specimens 5 years old from seed were 4 metres tall even though growing in a very windy site in Cornwall[K]. This species has a symbiotic relationship with certain soil micro-organisms, these form nodules on the roots of the plants and fix atmospheric nitrogen. Some of this nitrogen is utilized by the growing plant but some can also be used by other plants growing nearby[28][9]. Nitrogen-fixation by trees up to 8 years old has been put at 125 kg/ha/yr., for 20 years at 56 - 130 kg/ha/yr.[16]. Trees often produce adventitious roots from near the base of the stem and these give additional support in unstable soils[8]. Trees are very tolerant of cutting and were at one time much coppiced for their wood which had a variety of uses[18][8]. Alders are an important food plant for the caterpillars of many butterfly and moth species[17] and also for small birds in winter[13].There are 90 insect species associated with this tree[13]. There are some named varieties, selected for their ornamental value[9]

References

  1. F. Chittendon. RHS Dictionary of Plants plus Supplement. 1956 Oxford University Press 1951-00-00

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  2. Polunin. O. Flowers of Europe - A Field Guide. Oxford University Press 1969-00-00 ISBN 0192176218

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  3. Bean. W. Trees and Shrubs Hardy in Great Britain. Vol 1 - 4 and Supplement. Murray 1981-00-00

    ↩1↩2

  4. Johnson. C. P. The Useful Plants of Great Britain.

    ↩1↩2

  5. Triska. Dr. Hamlyn Encyclopaedia of Plants. Hamlyn 1975-00-00 ISBN 0-600-33545-3

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  6. Holtom. J. and Hylton. W. Complete Guide to Herbs. Rodale Press 1979-00-00 ISBN 0-87857-262-7

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  7. Taylor. J. The Milder Garden. Dent 1990-00-00

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  8. Beckett. G. and K. Planting Native Trees and Shrubs. Jarrold 1979-00-00

    ↩1↩2↩3↩4↩5

  9. Huxley. A. The New RHS Dictionary of Gardening. 1992. MacMillan Press 1992-00-00 ISBN 0-333-47494-5

    ↩1↩2↩3↩4↩5↩6

  10. Lust. J. The Herb Book. Bantam books 1983-00-00 ISBN 0-553-23827-2

    ↩1↩2↩3↩4↩5

  11. Rottsieper. E.H.W. Vegetable Tannins The Forestal Land, Timber and Railways Co. Ltd. 1946-00-00

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  12. Bown. D. Encyclopaedia of Herbs and their Uses. Dorling Kindersley, London. 1995-00-00 ISBN 0-7513-020-31

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  13. Baines. C. Making a Wildlife Garden.

    ↩1↩2↩3

  14. Chevallier. A. The Encyclopedia of Medicinal Plants Dorling Kindersley. London 1996-00-00 ISBN 9-780751-303148

    ↩1↩2

  15. Hills. L. Comfrey Report. Henry Doubleday Research Ass.

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  16. Duke. J. Handbook of Energy Crops - 1983-00-00

    ↩1↩2↩3↩4↩5↩6↩7↩8↩9↩10

  17. Carter D. Butterflies and Moths in Britain and Europe. Pan 1982-00-00 ISBN 0-330-26642-x

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  18. Grieve. A Modern Herbal. Penguin 1984-00-00 ISBN 0-14-046-440-9

    ↩1↩2↩3↩4↩5↩6↩7↩8↩9↩10↩11↩12↩13↩14

  19. Uphof. J. C. Th. Dictionary of Economic Plants. Weinheim 1959-00-00

    ↩1↩2↩3

  20. Arnold-Forster. Shrubs for the Milder Counties.

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  21. Mabey. R. Plants with a Purpose. Fontana 1979-00-00 ISBN 0-00-635555-2

    ↩1↩2↩3↩4

  22. Usher. G. A Dictionary of Plants Used by Man. Constable 1974-00-00 ISBN 0094579202

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  23. Freethy. R. From Agar to Zenery. The Crowood Press 1985-00-00 ISBN 0-946284-51-2

    ↩1↩2↩3↩4↩5

  24. Chiej. R. Encyclopaedia of Medicinal Plants. MacDonald 1984-00-00 ISBN 0-356-10541-5

    ↩1↩2↩3↩4↩5↩6

  25. Rosewarne experimental horticultural station. Shelter Trees and Hedges. Ministry of Agriculture, Fisheries and Food 1984-00-00

    ↩1↩2

  26. Sheat. W. G. Propagation of Trees, Shrubs and Conifers. MacMillan and Co 1948-00-00

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  27. Launert. E. Edible and Medicinal Plants. Hamlyn 1981-00-00 ISBN 0-600-37216-2

    ↩1↩2↩3↩4↩5↩6

  28. Gordon. A. G. and Rowe. D. C. f. Seed Manual for Ornamental Trees and Shrubs.

    ↩1↩2↩3

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